The present invention relates to a resin composition comprising ethylene-based polymers or, more particularly, to a resin composition comprising ethylene-based polymers with excellent moldability and capable of giving shaped articles having excellent mechanical properties.
As well known, high-density polyethylenes are unusually prepared by the polymerization using a Ziegler catalyst and the molecular weight of the current products of high-density polyethylene is relatively high as a trend in consideration of the improved mechanical strength of the articles shaped of the polyethylene resin. A problem encountered in the molding works of high-density polyethylene resins having such a high molecular weight is the workability of the resin and, when the polyethylene resin has a narrow molecular weight distribution, the resin is poorly flowable to cause a great decrease in the productivity of the plastic fabrication along with an increase in the power consumption due to the higher pressure on the molten resin under fabrication.
In order to solve the above mentioned problem, several attempts have been made to manufacture a high-density polyethylene resin excellent in the moldability and the mechanical properties of the shaped articles by the methods of melt-blending, multistage polymerization and the like. Unfortunately, none of the attempts has been quite successful in producing a polyethylene resin having moldability suitable for blow molding and inflation molding.